The present invention relates to an improved tamper evident composite closure and its method of manufacturing and more particularly to a composite closure having a molded plastic ring or skirt portion and a metal or other separate cover portion which is snapped into position at the top of the ring portion.
There are presently in use a number of composite closure caps for sealing containers which comprise a molded plastic ring or skirt portion and a metallic cover or disc which is inserted into the upper portion of the ring for completing the closure. These known closures are presently manufactured with plastic cover portions at the tops of the plastic rings for engaging an containing the separate covers. The presence of these partial covers or top flanges have caused the plastic ring to be molded so that the completed rings are stripped outwardly of the mold with the cover portion foremost. Such a molding process follows naturally from the molding or plastic closures having a full cover requiring the mold stripping to be cover first. For such molded plastic closures, with at least partial cover portions, such a molding operation is suitable and satisfactory.
More recently, however, composite closures formed of plastic rings and metal covers have added tamper indicating members at the bottoms of the molded skirts in the form of projections or locking tabs or fishhooks. Stripping such plastic rings in such a manner that the tabs or fishhooks are drawn over the remaining portions of the core has tended to destroy the tabs or fishhooks or to require them to be initially molded without any significant radially inward projection.
Accordingly, a molding method in accordance with the present invention is provided where the cover or partial cover is eliminated and the tabs or fishhooks are provided with a significant inward projection.
The composite closure cap of the present invention provides a new means for attaching separate cap covers to the tops of molded plastic ring portions and also permits a ring design with tabs or fishhooks of substantial inward depth. The molded rings in such a mold are stripped from the mold with the fishhooks being drawn outwardly from the mold without interference and with there being no significant cover portion on the molded ring to interfere with such an outward stripping movement.
Accordingly, the object of the present invention is to provide an improved composite closure cap and a method of manufacture.
Another object of the present invention is to provide an improved composite closure cap with a means for attaching a separate cover which avoids inwardly projecting full or partial plastic cover portions on the ring.
Another object of the present invention is to provide an improved tamper evident composite closure cap with premolded inwardly projecting container engaging tabs or fishhooks.
Another object of the present invention is to provide an improved method of molding the plastic ring portion of a composite closure cap.